Mail API endpoints: download attachment, unread count, read count, views

I am integrating zoho mail into my application. I can't find a good way to see unread email count. I don't want to write my application to potentially loop hundreds or thousands of emails to count the amount of status unread. I also need to be able to download attachments in my app. All I see is how to get attachment information. But no way to retrieve the attachment. Last, is there any way to see views with the API?